Manufacture of printing-plates.



M. A.. DROITCOUR.

MANUFAGTURE 0F PRINTING PLATES.

APPLIOATION FILED APR. 1a, 1910.

Patented Nov.' 21, 1911.

Hoz/nut f UNITED sTATEs PATENT ormoni.

4 v MICHAEL A. DROITCO`UB,` 0F OAK PARK, ILLINOIS,ASSIGNR T0 MIEHLE-PRINTING rnEss `Nn MANUFACTURING COMPANY, or CHICAGQTLLINCIS, AConPon'ATIoN y OF ILLINOIS.

`Application illed April 18, 1910. 'Serial No. 556,158.

To all 'whom it may concern:

` Be it lmown that LLMionAnL A. Diiorr- Coun, of Oak' Park, infthe county of'Cook facture of Printing-Plates; and I hereby declare that the following is a full, clear, and exact description thereof, reference vbeing had to the accompanying drawings, Which form part of this specicatlon.

This invention isl a novel process or method of producing so-called madeready For toned 'printing plates; and the object of this invention is to .produce -a perfectly toned printing'plate in avery simple but most effective manner, and by means of this process the plate is toned as it is being formed s olthat when completed it is ready for immediateuse and- Without subsequent distortion of its printing surface Will produce impressions having the desired lights and solids or tones.

In brief my invention consists in makingI a shell,-such as an electrotype--of copper or other; suitable metal from the matrix 0I' printing surface ina'the ordinary Way,- such shell being very thin and flexible; such shell is then placed face downward over aA unable-toning member, such as a previously prepared positive underlay placed in register therewyzh; which underlay is made in any suitable Way so as to have projections on its face at the places Where it is desir'ed to have depressions or high lights in the" nished printing surface; and depressions -on its face Where it is desired to have projections or solids in slch printing surface. Theshellis then subjected to fluid pressure so as to make its face reversely' 40 conformed to the opposed toned surface of the toning member, and then the shell'is backed. Preferably I tone and back the shell by placing the shell and toning member .iipon a perfectly true plane surface,

such 'as a cast-iron plat/eg a chase or metal frame is then placed over and rests4 upon the marginsof the shell, so as to hold the same closely in contact With the margins 4of the positive underlay; then suiicient molten met-al, of the usual lkind employed to `back up the shellfis poured into the chase and l upon the shell, to form with the shelllaf printing plate of thedesired thickness; the

` shell is then sealed by closing the chase with* l,suitable metal plate pr cover, constructed u ftd-form an air-tight joint with the chase, and State of Illinois, have invented certain* :and while the chase, shell and underlay are 5 new vanduseful Improvements in the Manuhel'd closely together and against the bed on which they are supported, compressed air, or other suitable fluid, is admitted into the chase, above the molten metal, under sufficient pressure to force 'the shell toward the bed at all points Where it is not supported-by projections on the of the ton-y ing member or underlay; and thus compels the` negative face of the shell to conform to the positive face of the underlay, but of course the reverse thereof,in that the face of the shell will be recesfsed or depressed Where the face of the underlay projects,

and vice versa. After the metal is set the chase is removed, and the complete platecomprising the metal backing and the shell facingis shaved or planed in the usual Way, and preferablywhile the. shell face is still in contact with theunderlay, so as to reduce the plate to the desired thickness and give its backa true plane surface; and

finally, the plate is separated from the overlay andits margins trimmed and beveled as usual. Such plate is then ready for use -withoutany manipulation or distortion of printing surface, which is already its toned in accordance with the underlay,

and ready for printing and will producel the desired lights and solids in .the

impressions taken therefrom. In making printing plates such as tint blocks Which require a plane printing surface and uniform pressure in printing, a like process can be used, except that an underlay is unnecessary ;-in such -cases the shell beingfirst formed is laid face down upon and in contact with the fiat surface' of the supporting plate or bed; then the chase is placed thereover, and the molten metal introduced and subjected to air pressure asdescribed, so as v to force the face of the shell at all points into direct contact with the plane surface of the bed, so that the resultant printing plate will have a true plane surface.

An important feature of the invention is the subjecting of the shell to air, or fluid,

pressure, to produce the desired toning of its face, and backing the toned shell to form a,

plate, without altering inl any Way its previously formed printing surface ;-and if the same has been toned, as above described, leaving the tones entirely unchanged. By subjecting the molten metal to fluid pressure while confined in the chase, the metal is kept in close contact at all points with the shell while the latter is forced into Contact withthe underlay. or bed at all points with' uniform pressure. These desirable results cannot be as successfully accomplished by subjecting the metal in the chase to the action of a plunger because the 4molten metal is subject to contraction and chill and the pressure Would not be uniformly distributed therethrough, while by reason of the flexible air pressure all the distortional effects of shrinkage in the metal will appear at the back of the plate, .but

the face of the shell will alwaysbe held in forcible contact with the underlay or bed by reason 'of the constant pressure upon the to toning and-'backing back of the metal, which pressure is uniform at all, points, both awhere the projections are on the underlay as Well as where the recesses appear therein. The tendency of the molten metal is to assume a uniform level and thus form a smooth back on the shell-and at the same time any contraction in the metal due to chilling is readily compensated for by the flow of metal itself vunder pressure in vthe softer parts thereof before it -becomes set.

In -the accompanying drawings I have- Iillustrated one method of making a toned printing plate in1accordance with this invention. r

In the drawings,-F igure lis a perspective VView of an'electrotype-shell preparatory 4 same. Fig. 2 is a longitudinal'section through the shell, Fig. 1. Fig. 3 is asection through the positive underlay. Fig. 4- is a sectional view showing the shell, underlay and backing met-al 1n chase, preparatory to applying the air pressure to the backing of the shell. Fig. 5 is a view similar to Fig. 4 showing the effect of the pressure applied to' the metalbackmg of the shell. Fig. 6 shows the formed plate in positionfor shavingthe backthereof.' Fig.'

7 is an enlarged sectional view of part-of a finished plate.

The printing surface of thel 4plate is forred of' ainetal shell S, which may be' produced inanyl desired manner, as by electrically depositing a vthin 'skin ofmetahA such as copper,upon a negative vmatriz; corre'- spondmg -to the 'Printmg surface desired, rlhis shell'v'S will of course have minute pro jections on its face corresponding to the type or printing portions of the surface, and will have corresponding .depressions on itsvunder side, but it will nevertheless bei* approximatelyplane surfaced on both'sides, so that an impression taken therefrom would appear' uniform in color and 'without' any' lights high-lights, solids, etc., iny

the impressions taken from the finished printing plate, it is necessary to vary the height of the printing surface of, such plate, making it lower or de ressed where lights .are desired, and ma 'ng it higher Where solids are desired. These gradations are practically imperceptible to the eye in the plate, itself, but are essential in producing ne workand I produce these tones in the manufacture of the plate as follows: Assuming that it is 'desired to have portions of the surface of the finished late raised at the points indicated at a in ig. 2, so 4as to obtain greater pressure thereon at such points, a positive underlay U is formed in any suitable manner, as by taking a series of impressions from the original type surface upon sheets of paper and building u p therefrom a positive underlay in a manner' well' lmown to the trade; but, such underlay can be formed in any other desired manner, and from other materialfitonly being essential that the underlay U have depressions'a in its face, see Fig. 3, corresponding to the points a, a, Fig. 2,- where the lsurface'of the finished printing plate is to be elevated; and said underlay has projections a on its face where the surface of the finished printing plate is to be depressed. The relative.

size, depth, height and location of the depressions and projections on the underlay are ofcourse determined by the operator in .accordance with the tonesv which it is desired to have inthe impressions taken from the finished plate. 'The positive face of the underlay U 1s then p laced inregister with4 the negative face'of the shell, and bothv are placed upon a flat-surfaced bed. B, Fig. 4, with the `shell .on top of the underlay, the flat type or printing-surface of the shell belng -contact with the uneven surface of' i the u nderlay.. A metal chase' C of Suitable `size 1s then laid uponthej'margin's of\,the shell so as to press them and the underlying portions of the underlay closely against the surface of the bod B, and form a. seal around the shell. The chase is preferably made thicker than the plate to. be formed'.A A suiiicient `quantity of. molten metal M is then. poured into the chase to back up the printing plateof r surface ofthechase .fthe bottom 'of the Ik"to besubj order to tone it. A

In the manner, 'above described the shells i figoefseo chase andtho margins of the shell, Then air, or other suitable fluid, is admitted from a suitable reservoir- (not shown) by means of a lpipe p into theair 'space o r chamber formed in the chase under plate P and-above thetmetal M,' -'I'prefer to use air at a pressure of about Opounds. The molten metal naturallyassumesits level, Fig. 4, and when the air pressure isA applied thereto the4 shell is uniformly forcedtoward `the' bed' and against the .underlay U, and the exterior printing surface of the shell is forced to conform reversely to the uneven'surface of the nderlay; i'n other words the negative printing surface ofthe shell is made to conform with the" depressions and projections on the positive-surface of the underlay, the surface of the shell of course becoming the reverse of the surface of the underlay, being depressed where the underlay has projections and projecting where the' underlayis depressed. 'Ihe pressure is continuedl until the metal sets, and then the platen P is. re moved, and the chase withdrawn from the backed shell, and the formed plate-while still applied to the underlay asin Fig'. 6 has itsjrear face smoothed or brought kto a plane surface by means of a cutter T (Fig. .6),.or any -othensuitable means, by which surplus .metal is removed from the back of the plate-,'as indicated by line 'mf-min Fig. 6, to reducethe late tothe desired thickness, with a uni ormplane surfaced .back. The underlay U is thenremoved from thet face 'of the plate,- but the shell remains a permanent part of the inished'plate, which, as shown in Fig. 7, has depressions a? in its face correspondin with-the projections a.2 in the underlay. bviously properly varying. the surface of the un erlay any desired tones may be given the printing s1'. 1r`

face,' and while I lhave-.described theunderlay' as if formed 'of superposed layers-of 4paper it is obvious' that the invention does not depend upon the particulamstructure of the underlay. lIt will be seen from 4the foregoing descrip- .tion that the plate is toned as and vwhen made; and'all that has'to be done after the plate is formed as described is to trim oit the' unnecessary margins 'and bevel the edges ofthe plate,las usual, to enable it to be secured in the press.' Care should be taken insuch trimming not to injurethe [toned face of the plate which-'should notibe "disturbed 4after it-is `formed, and need not ected to any subsequent -'distoition insults for the reason' that the thin lshell or surface of the printing plate alone has to be toned, andthe metal of the backing being molten at' the time of the toning operation, does not have tobe stressed or strained at all and is.utilized in eectin 'the toning of Athe plate byiiuid pressure with absolute accuracy and certainty.

'with molten metal, any'other. backing that Imight be found suitable for such purpose could be employed.

The invention is alsouseful, as above the back of said shell to forma plate therewith;y and finally, subjecting the. shell tn suicient air pressure to cause the surface at the shell to conform to the toning member; removing the plate from' the press, and re# ducing its back to a plane surface'whileits face is appliedto the toning member, and finally removing the toning 'member and trimming the plate.

2. The process of forming printing plates, consisting, in first makinga thintype shell -or surface; 2nd superposing said shell upon a positive underlay; 3rd supplying suiicient form a plate therewith; 4th. subjecting the shell to suiiicient pressure to ca the surface of the shell to 'conform to thlseinderlay; 5th reducing its back to a plane surface while its face is applied to the underlay;

ming theoplat'e.' 3. The vprocess of forming toned printing plates, consisting in first. making a thin printing-surfaced shelll with margins; 2nd

a l in a tonin member to the rinting sipfgce gif such slell and'laying thn upon Aa plane surfaced support; 3rd placing a chase around Aand upon the'margins of said shell; 4th pouring-molten metal into the chase; and- 5th subjecting the' shellto sutilcient pressureto cause the surface of the shell. to conform to the toning member.

4. T he process 'of forming toned printing plates, consisting' first ,making a thin printing-'surfaced shelLwithmargins; 2nd applying a toning 'member to the printing surface ofsuch shell land laying them upon a plane surfaced support; 3rd placing a chase around and upon the-margins of said shell," ithhpouring vmolten 'metalinto the chase; 5th'subject1ng-the`she1l to suieient 'pressure tojcause the surface l'of the shell to conform to the member, and continui While I have described the shell as backed stated, i-nma'lring plates with uniform printing surfaces, the use of air or fluid pressure a toning member; 43rd .supplying metal fo molten metal to the back of said shell to f and finally, removing the underl'ay and trim- I shell; 4th

vplate to a plane surface while applied toV Ithe toning member; and removing said member'. 5. The process of forming toned printing plates, consisting in, first making a thm printing-s'urfaced` shell with margins; 2nd

applying positive underlay to the printing surface o' such shell and laying them upon a plane surfaced support; 3rd placing achase around and. upon the margins of said pouring molten metal into L' the chase; 5th subjecting the shell to suiiicient air pressure to cause the surface of the shellto conform` to the underlay, and continuing the pressure until the backing. metal is prop;

erly set; 6th removing'. the plate from the press, and reducing its back to a plane surface While its. face is applied 4to the under-lay, and inally, removing the underlay and trimmingthemargins of theplate..

6. The processo`f` making toned printing surfaces, .consisting informing a printing surfaced shell, applying a toningmember to the'fa'ce of such shell, and subjecting the. back of the shell to fluid pressureto cause itsprinting surfaceto reversely conform to the surfaceofth toning member and back- I ingfthe toned shell.l 4

8. The process of making toned-printingplates,consisting in forming a flat. printing to the j ecting the back ofthe shell to fluid ressure';

7 The process -of making toned surfaces, c ons` in' forming. a faced shell, applying a tonin the printing surface of such s ell, subject# ingl the back of theshell to iiuid pressure to cause the printing surface of the shell to this .reversely conform to the toning surface ofsaid member; and bac the toned shell. V

surfacedshell applying-'a tonin member printing surface of, the sell, subto cause lthe printingsurface 'of e shell to reversely 'conform to the surface ofithe toning member,`and attaching-a -v'suitable .backing to the toned 'shell while under such pressure.

9.v The process of making toned 'printing plates, consisting in mak'ing a printing surfaced shell, lacin Ya toning member against the face of t e she applylng fluid pressure tothe back' of the shell to cause itsprinting surfa'ceto reversely conform'to the sur-v fact` of the toning' member, apglying molten metal to thebackl of the she while it. is underV such pressure, and continuing the pressure until suchmetal sets.

-10. .The process of making toned rin'ailg plates, consisting in forming a printing-surfaced shell, applying a toning member Ato the face thereof, placing achase thereoYer and sealing the chase, supplying molten -metal-in the hseto form a backing for the shell, and then-subjecting the shellto fluid pressure until the'moltsn metal-sets. y

member to 11. The process of forming toned printing plates, consisting in making a printmg-surfaced shell, superposing said shell upon a toning member, and finally subjecting the back ofthe shell to.- suiicient air pressure to cause the surface of the shell to conform to the toning member, and backing the toned shell while under such ressure.

12. The process o plates, consisting in first makin a thin metallic printing surfaced type she 2nd placing the printing face of said shell a ainst a toning member; 3rd applying s cient molten metal to the back of said shell to form a platev therewith; and finally, subjecting the metal and shell'to suiiicient air pressure to cause the surface of the shell to conform to the toning member.

13. The 'process of forming plates, consisting in preparing a thm metal printing#surfaced shell, placingsame face downward lunder a chase upon al suitable' support, sealing the chase, pouring suiiicient '.molten metal .into the 4sealed chase Ato back the shell andv form a plate, and admitting compressed air intothechase and continu" forming printing A printing ing the pressure until the molten metal :'sets.

plates, consisting in first making a prmtingshell upon a plane surfacedl support; placmg achase around and upon the margins of said'shell and sealing the chase; pouring l molten metal into the chase to form thebacking of the shell; introducing compressed air into the sealed chase; and continuing.. the pressure until the backing metal is prop- Aerlyset; removingthe plate from the press, and reducing its back to a plane surface; .a111d inally, trimming the margins of the p ate;

^15 V The process of making toned printing surfaces consisting informing a. printing surfaced shell, aplplying a toning member to the face of suc s ell, andsub'ecting'the face and back of the shell to di erent fluid pressuresto cause itsl printingsu'rface to reversely conform -to the suiface of the toningmember, and backing the toned shell.

16. The process of making toned rinting surfaces consisting in forming a faced shell, appl i' a to member to the printing .sur ace of such s ell, subjecting the face and back of lthe shell to different toned printing.'

surfaced shell, applying a tonin member to the printing surface 'of the she subjecting the face and back ofthe shell to different fluid pressures .to cause the printing' surface of the shell tov reversely conform to lso - the face of the shell, applying di erent fluid pressures to the face and back of the shell to cause its printing surface to reversely conform to the surface of the toning member, applying molten metal to the back of the shell while it is under such pressure, and continuingthe pressure until such metal sets. r

19. The process of forming toned printing plates, onsisting in making .a printing surfaced shell, superposing said shell upon a toning member, and inally subjecting the face' and back of the shell to different air pressures to cause the surface of the shell to conform to the toning member, and backing the toned shell'while under such pressure.

20. The process of forming printing plates, consisting in first making a thin lmetallc printing surfaced type shell; 2nd, placing the printing face of such shell against 'a toning member; 3rd, applying suticient molten metal to the back of said shell to form a plate therewith, and, finally, subjecting the back of the metal and the -:tace ofthe shell to different air pressures to cause the surface of the shell to conform to'the toning member.

In testimony that I claim the foregoing as my own, I aflx my. signature in presence of two witnesses. i 7 A l MICHAEL A. DROITCOUR.

Witnesses:

SYLVIA J. WILLS, Roer. A. LAGHMANN. 

